This has happened 3 times now.
There is one pic in 1st position, which stays put.
I can add one more into 2nd position, but then any subsequent pic, although labelled as 3rd position, goes into both 2nd & 3rd, & previous 2nd is gone. (I haven't tried to go as far as 4th!)
This is on ipad, as all the pics I want to upload are there